McClain County, OK Insulation Payback
McClain County, OK: what topping up your attic actually costs
McClain County, Oklahoma is zone 3 under DOE's climate map (Mixed-Humid), which means heating load in winter and cooling load in summer, both worth taking seriously here. An uninsulated attic there should be built up to R-49. For an attic around 1,000 square feet, closing the gap from R-2 to R-49 costs around $2,820 and saves an estimated $1,193 a year — payback in roughly 2.4 years. That's about as fast as attic paybacks get.
Where the savings come from
The estimated savings split roughly $874/year heating, $319/year cooling. Out of every 100 US counties tracked here, McClain County's savings potential beats roughly 31 of them. Within zone 3 specifically, it ranks 105th of 690 counties by estimated savings. Oklahoma averages $1,260/year across the counties tracked here; McClain County comes in 5% lower.
The climate data behind this
McClain County's climate figures — 3,295 heating and 2,003 cooling degree days a year — are read from PURCELL 2 SW, OK US, 4.3 miles away, NOAA's nearest 1991-2020 normals station. That combined heating-and-cooling load ranks McClain County 2066th nationally by total degree days — the 35th percentile. McClain County falls in DOE's moisture regime A (humid), a detail that affects vapor-barrier recommendations more than the R-value target itself.
If the attic isn't bare
A shallower starting point changes the math: with R-11 already down, only the gap to R-38 needs filling, at roughly $1,620 for an estimated $161/year saved (~10.1-year payback). This one is a genuine toss-up, not a clear yes.
Next steps for a McClain County attic
Get more than one quote before committing. Attic access and any needed air sealing move the price around, and most contractors won't take a job below roughly $600 regardless of size - worth asking upfront given McClain County's estimated $1,193/year on the line.
Nothing here is a guess
Every figure on this page traces to DOE/IECC climate zones and NOAA degree-day normals, documented in the methodology guide. The guide to what R-value actually means explains why R-49 is the target here specifically.